This invention relates to rotary internal combustion engines of the trochoidal type, and more particularly to throttling means for such engines, as well as means for controlling the intake port timing.
Engines of this type have a peripheral shell having a multilobed trochoidal inner surface and a pair of side walls defining an engine cavity, with a rotor of generally polygonal profile mounted for rotation on an eccentric portion of a shaft within the cavity, the rotor also performing a planetary motion therein. The apex portions of the rotor continuously sweep the inner trochoidal surface of the shell in sealing relation, forming with the cavity walls a plurality of chambers of variable volume in which the phases of induction, compression, expansion, and exhaust take place.
Intake and exhaust ports may be disposed either in the peripheral shell and controlled by the rotor apexes, or in one or both side walls and controlled by the side faces of the rotor sliding over the ports, or in some combination of the two systems. When a side intake port is provided in at least one side wall and controlled by the rotor side face, comparatively good idling and partial-load performance can be obtained, but there is the difficulty that the throttling device is normally disposed in the induction channel at a considerable distance from the port opening in the engine chamber. Therefore, there exists some unmixing of the fuel-air mixture and condensation of small droplets of fuel on the walls of the induction channel. Even if a throttle flap were disposed relatively close to the port, its axis must be positioned at a distance of at least half the diameter of the flap from the port in order that the flap should not protrude into the engine cavity. Even this arrangement leaves some length of channel, and particularly for idling and partial-load operation the mixture arriving at the port may not be adequately prepared. Further, such an expedient would necessarily require that the port be circular rather than elongated in the direction of rotor motion, as is preferable.
The foregoing defects and disadvantages are corrected by the throttling device of the present invention.